The Argument for a Vegetarian Diet
Part Threeby Gary Null, PhD, and Martin Feldman, MD

From the Townsend
Letter
July 2009

The Argument for a Vegetarian Diet
 Part 3

By Gary Null, PhD, and Martin Feldman, MD

In Parts 1 and 2 of this series, we presented key aspects of the argument in favor
of a vegetarian diet. Part 1 discussed misconceptions about protein, the bodys
protein requirements, and the assessment of protein quality. Part 2 discussed the
ecological mandate for a vegetarian diet, detailing how our finite natural resources can
be used much more efficiently to produce plant foods than animal products. In this final
installment, we present evidence that a plant-based diet can have far-reaching health
benefits.

It has been 13 years since the U.S. Secretary of Health and Human Services first
endorsed the healthfulness of a vegetarian diet. The data have been in for decades now,
and they show that vegetarianism offers incontrovertible health benefits. Hundreds of
studies in peer-reviewed journals support the advantages of vegetarian eating.
As stated by one researcher, A growing body of scientific evidence indicates that
wholesome vegetarian diets offer distinct advantages compared to diets containing meat and
other foods of animal origin.Another
paper reports, Numerous studies show important and quantifiable benefits of the
different components of vegetarian diets, namely the reduction of risk for many chronic
diseases and the increase in longevity .An abundant consumption of vegetables,
fruits, cereals, nuts, and legumes all have been independently related with a lower risk
for several chronic degenerative diseases, such as ischemic heart disease, diabetes,
obesity, and many cancers.
It is important for healthcare professionals to share this information with patients. Many
people believe that news about nutrition reported in the media presents conflicting
information, and as a result they may develop a defeatist attitude regarding their food
choices. But there is no disagreement about the value of a well-balanced vegetarian
approach to eating. Reaffirmations that vegetables, whole grains, and other plant foods
have been shown, yet again, to be healthy will quell any uncertainty and may even be
life-saving.

IMPROVING HEART HEALTH
Many studies have shown that a vegetarian diet can affect risk factors for cardiovascular
disease, which remains the number one cause of death in America.
In a study comparing healthy postmenopausal vegetarian women with omnivores, the
vegetarians had statistically lower systolic and diastolic blood pressure (BP), along with
lower total cholesterol, low density lipoprotein (LDL) cholesterol, triglycerides, fasting
blood sugar, and hemoglobin levels.Other
research has found that people eating a low-calorie, low-protein vegan diet had lower
systolic and diastolic BP than two other groups studied: endurance runners eating a
Western diet and sedentary people eating a Western diet. Both the vegans and the endurance
runners had lower levels of lipids, lipoproteins, glucose, insulin, C-reactive protein,
and BP than did the sedentary Western diet group.A study of vegetarians aged 35 to 64 in Brazil also found that they
had lower BP, total cholesterol, LDL, triglycerides, and glucose than did meat-eaters.
The following data support the positive effects of vegetarian eating on risk factors for
cardiovascular disease:

Reduced blood pressure. The ability of a vegetarian diet to
reduce blood pressure has been documented numerous times. In fact, one study notes that
scientific interest in this effect of a meat-free diet dates to the early decades of the
20th century.Thats
when it was shown that patients hypertension was worsened by meat consumption, and
that when vegetarian college students began eating meat their blood pressure increased
significantly within two weeks.
According to one article, there is  strong evidence for a blood-pressure
lowering effect of a lacto-ovo vegetarian diet the effect is independent of sodium
and energy intake and of other aspects of lifestyle that tend to characterize vegetarian
populations.These authors
added, Cardiovascular risk in general is low in people adhering to a lacto-ovo
vegetarian diet, not only because their blood pressures are lower and tend to rise less
with age, but also because they carry less excess fat and tend to have healthier blood
lipid profiles than do meat eaters.
A study of Seventh-Day Adventists, a religious group that encourages abstinence from meat,
alcohol, caffeine, and tobacco, found that they had lower systolic blood pressure in early
adulthood than two other groups, and that systolic BP increased less with age. The same
was true of diastolic blood pressure. The researchers noted, The differences in
plasma lipid levels between Adventists and other population groups can be explained by a
vegetarian diet, and this may have contributed also to the blood pressure levels.

Improved lipid profile.Research into the chemistry
of plants indicates that the phytosterol group has heart-healthy effects. Studies have
shown that the intake of plant stanols or sterols reduces LDL cholesterol,,which is one of the
factors responsible for the plaque buildup that causes atherosclerosis. This
intake also increases the percentage of plant sterols readily available to be absorbed by
the intestinal cells, the enterocyte.
In a meta-analysis of 41 trials, researchers found that 2 grams per day of stanols or
sterols reduced LDL by 10%, and that eating foods low in saturated fat and cholesterol and
high in stanols or sterols can reduce LDL by 20%.Significant decreases in LDL were found in a study comparing the
effects of a statin medication with a diet high in cholesterol-lowering foods, including
plant sterols, soy protein, viscous fibers, and almonds. The mean decreases in LDL were
30.9% for the statin group and 28.6% for the dietary portfolio group, a difference that
was not significant.
Studies of vegetarians support the positive effects of vegetarian eating on cholesterol
levels. In a comparison of healthy elderly vegetarian women with nonvegetarian peers,
vegetarian eating was associated with lower lipid and blood glucose levels.Another study compared Adventist
vegetarians with Mormons who also had a strong religious affiliation and avoided caffeine,
alcohol, and tobacco. The groups differed only in their meat intake. In this way, the
study could avoid a common problem in comparing Adventists with meat-eating members of
society at large: the possibility that other lifestyle factorsreligion and
abstinence from substances besides meatmay confound the results. The study found
that the vegetarian Adventists had significantly lower cholesterol levels, blood pressure,
and obesity than did the Mormons.
Other research with Seventh-Day Adventists studied the effect of different levels of meat,
fish, and fowl consumption on cholesterol levels in vegetarians and nonvegetarians who
were matched according to physical and demographic variables. The study concluded,
With the exception of those under 25 years of age, the results showed that
nonvegetarians had higher serum cholesterol levels than the vegetarians.
In another study, even those under age 25 showed the adverse effect of meat consumption on
cholesterol levels. This study divided Adventists aged 12 to 17 years into two groups:
those who occasionally or regularly ate meat, fish, or fowl, and those whose protein came
entirely from dairy and vegetable sources. The vegetarian youngsters had significantly
lower cholesterol levels than did their meat-eating peers. While adolescents generally do
not have to worry about heart disease, patterns established early in life tend to be
carried into later years, when health risks increase.In addition to blood pressure and cholesterol levels, triglyceride levels have
been shown to be adversely affectedthat is, raisedby meat consumption.,

Lower risk of mortality from heart disease. Perhaps it is most
significant to look at the coronary heart disease picture from the perspective of
mortality. A comparison of vegetarian and nonvegetarian Seventh-Day Adventists found that
the risk of fatal coronary heart disease among nonvegetarian males, ages 35 to
64, is three times greater than [that of] vegetarian Seventh-Day Adventist males of
comparable age. The report cites lower intake of total or saturated fat and higher
intake of dietary fiber as probable factors in the better statistics for the vegetarian
group.
According to another report, studies at Loma Linda University revealed that
Seventh-Day Adventists (aged 45 to 54) who eat meat six or more times per week are three
times as likely to die of heart disease as vegetarian Seventh-Day Adventists.

REDUCING CANCER RISK
A wealth of published data points to a plant-based diet as a way to prevent cancer. An
important paper on the incidence of cancer among Seventh-Day Adventists in California
(where many Adventists live) reported links between diet and many types of cancer. A high intake of meat was
associated with a twofold increase in the risk of bladder cancer, and higher intake of
saturated fats was associated with greater risk of colon cancer. On the other hand, the
following associations were found: higher consumption of fiber and legumes with lower risk
of colon cancer; high consumption pattern of beans, lentils, peas, tomatoes, raisins,
dates, and other dried fruits with lower risk of prostate cancer; high intake of fruits
with lower lung cancer risk; and higher consumption of soy-based products with markedly
lower risk of pancreatic cancer.
A recent prospective study examined meat intake and cancer risk among approximately
500,000 participants (aged 51 to 70) in the National Institutes of Health-AARP Diet and
Health Study. People in the highest quintile of red meat intake had statistically
significant increased risks (ranging from 20% to 60%) for esophageal, colorectal, liver,
and lung cancer. In addition, people who ate the most processed meat had elevated risks
for colorectal and lung cancer.The
International Journal of Cancer has reported that cancers of the colon, rectum,
pancreas, breast, ovary, uterine corpus, and prostate are correlated with the amount of
animal products used in various countries.Other research has found that the risk of fatal cancer among
Seventh-Day Adventist males is 53% of the risk among all U.S. white males of comparable
age. For Adventist females, the risk is 68% of that in all U.S. white
females.
What might account for the lower cancer rates of Seventh-Day Adventists? An article in the
Journal of Environmental Pathology and Toxicology offers this analysis:
Perhaps as a result of their vegetarian diet, Adventists have a lower intake of
benzopyrene and nitrosamines and a higher intake of flavones, which are strong inducers of
the enzyme systems responsible for detoxifying such carcinogens. In addition, they may
have a higher intake of vitamins A and C, recently suggested as possible protective agents
against certain chemical carcinogens. Thus, it seems reasonable to suggest that the
typical Adventist diet may protect against many of the major sites of cancer.
Recent scientific plant research supports this data. Eating plant foods that have sterols
is correlated with lower occurrences of cancer; these results also may be related to other
cancer-fighting properties of the plant foods.
Another prime benefit of plant-based foods is their high fiber content. The importance of
fiber as a preventive measure against disease cannot be overstated. Fiber aids in the
speedy digestion and elimination of foods. It works like a scrub brush to scour away
accumulating deposits from the intestinal walls. Meat and other animal products, on the
other hand, do not contain fiber. They are difficult to digest and can remain in the
intestines for longer periods of time.

Colon cancer. The scientific literature shows that diet is an
important factor in colon cancer. One recent study concludes, Our data confirm that
colorectal cancer is positively associated with high consumption of red and processed
meat The results
of another study strengthen the evidence that prolonged high consumption of red and
processed meat may increase the risk of cancer in the distal portion of the large
intestine.A large-scale
analysis of dietary patterns and colorectal cancer, published in 2008, found that
dietary patterns characterized by a low frequency of meat and potato consumption and
frequent consumption of fruit and vegetables and fat-reduced foods are consistent with a
decreased risk of colorectal cancer.
From the American Journal of Clinical Nutrition:Recent
epidemiological studies associate colon cancer with specific types of diet. In general,
highly developed countries have a high incidence of colon cancer, and less well developed
countries have a low incidence. Japan represents an exception in that it is highly
developed but has a low incidence of large bowel cancer. Japanese who adopt a Western
diet, however, develop colon cancer with increased frequency; among Japanese immigrants,
the frequency approaches that of native Americans.It is noteworthy that the vegetarian-oriented
Seventh-Day Adventists have a colon cancer mortality rate only 61% that of the general
U.S. population for males and 70% for females.
According to Annals of Surgery, Epidemiologic data have also shown that the
incidence of cancer of all types, including carcinoma of the colon, is 30% to 40% lower in
American Seventh-Day Adventists than in the meat-consuming general public. Further
studies have shown that the levels of bile acids, as well as the degradation products and
enzymes responsible for the degradation of bile acids in the colonic lumen, are decreased
in this group of vegetarians.The bile acids referred to in this article are associated with colon cancer risk, and
they have indeed been shown to be lower in vegetarians.
From another report: Cholesterol and its metabolites, together with bile acids, are
implicated as risk factors in the genesis and progression of colon cancer 
Again, a high-meat regimen will increase levels of these harmful substances.

Prostate cancer. This is the most common cancer among men in
the U.S., according to a 2007 government report.A prospective study of dietary fat intake and the risk of prostate
cancer found a direct relationship between total fat consumption and advanced prostate
cancer. The association was due primarily to animal fat, not vegetable fat, and the food
group with the strongest association with advanced prostate cancer was red meat.
The mortality rate from prostate cancer for Seventh-Day Adventists aged 45 to 70 is only
30% that of males in the general population of California, suggesting that vegetarianism
may be a protective factor. Say researchers who have studied this subject,
Implications include the possible modification of prostate cancer risk through
dietary intervention.

Breast and endometrial cancers. Recent studies have shown
that a higher intake of red meat during adolescence may increase the risk of premenopausal
breast cancerand that higher
red meat consumption may be a risk factor for breast cancers that are estrogen and
progesterone receptor positive among premenopausal women.
Compared with the general female population, Seventh-Day Adventist women have a lower
mortality rate from breast and endometrial cancers, and the fact that 50% of them are
vegetarians seems to bear on this. Dietary patterns affect hormonal ones, and these are
crucial factors in womens disease risk.
One contributor to an increased risk of breast cancer, the leading cancer among women in
the U.S.,is early onset of
menstruation. And, in fact, the age of first menstruation (menarche) has been decreasing
in the U.S. and Western Europe. Our changing diet, with greater intake of fat, simple
carbohydrates, and meat, has contributed to this trend. But researchers writing in Medical
Hypotheses have proven experimentally that the present trend toward early
menarche can be reversed when a balanced vegetarian diet is selected in place of the
ordinary American diet.
Other researchers confirm the importance of this concept, noting that the maturation delay
of vegetarian Adventist teenage girls, compared with meat-eating schoolgirls, may
carry potential health benefits in adult life. A later age of menarche has been
consistently associated with decreased risk for several cancers, particularly of the
breast.

Pancreatic cancer. Processed and red meat was associated with
an increased risk of pancreatic cancer in an analysis of data from a large prospective
study. For processed meat consumption, people in the fifth quintile of daily intake had a
68% increased risk compared with those in the lowest quintile. For both pork and total red
meat intake, the increase in risk for those in the highest quintile was 50%.
On the other hand, Increasing consumption of vegetarian protein products, beans,
lentils, and peas, as well as dried fruit, was associated with highly significant
protective relationships to pancreas cancer risk.

Brain tumors. Research published in Neuroepidemiology
found that the growing consumption of meat and poultry was associated with increased
risk estimates for gliomas. This increase in risk was especially apparent for consumption
of pork products The report explained that since many
pork products are cured with sodium nitrite, this may be consistent with the hypothesis
that foods containing high concentrations of N -nitroso compounds may increase brain
cancer risk.

OTHER EFFECTS OF VEGETARIANISM
The following studies demonstrate the scope and depth of research on the health benefits
of vegetarianism:

Diabetes. A 2003 report on plant-based diets and type 2
diabetes concludes that the vegetarian diet contains a portfolio of natural
products and food forms of benefit for both the carbohydrate and lipid abnormalities in
diabetes.In one recent
study of people with type 2 diabetes, a low-fat vegan diet improved glycemic control and
cardiovascular risk factors, including weight and LDL cholesterol. After 22 weeks, 43% of
those eating the vegan diet had reduced their diabetes medications, compared with 26% of
participants eating a diet that followed American Diabetes Association guidelines.
In other research, a 17-year follow-up with members of Adventist Health Studies found that
long-term adherence (over a 17-year interval) to a diet that included at least
weekly meat intake was associated with a 74% increase in odds of diabetes relative to
long-term adherence to a vegetarian diet (zero meat intake). The researchers noted
that while some of this risk may be attributable to obesity and/or weight gain, weekly
meat intake was an important risk factor even after control for weight and weight change.
Other research suggests that a Western dietary pattern (with higher intakes of red and
processed meats, French fries, refined grains, and sweets and desserts) substantially
increases the risk of type 2 diabetes in menand may increase the risk in women.In addition, a 21-year study and follow-up found that
the rate of diabetes as an underlying cause of death in Adventists was only 45% of
the rate for all U.S. whites.

Body weight. . . . After controlling for height, boys
and girls in the Seventh-Day Adventist schools were found to be leaner than their public
school peers .... These results suggest that a health-oriented lifestyle in childhood and
adolescence, such as the one followed by Seventh-Day Adventists, is compatible with
adequate growth and associated with a lower weight for height.

Bone health. An issue of interest to older women is the
maintenance of mineral content in bones. Once again, vegetable eaters have an advantage.
Vegetarianism has been shown to contribute to strong bones in postmenopausal women.
Researchers explain, The primary dietary characteristics of a lacto-ovovegetarian
diet that may be of benefit to bone tissue are the sources of protein and quantities of
calcium and phosphorus in the diet. Investigators suggest that vegetable protein
produces a lower-acid ash than animal protein when metabolized and thus, helps to conserve
calcium.
The statistics back this up: In one study, Lacto-ovo-vegetarian women 50 to 59 years
of age lost 18% bone mineral mass while omnivorous women lost 35%.In another, vegetarian Adventist women
aged 55 and above have significantly less osteoporosis than the meat-eating
non-Seventh-Day Adventists.

Dental health. ...the dental and periodontal status of the
Seventh-Day Adventist group was significantly better than that of the controls, suggesting
that vegetarianism is beneficial to oral health.

Need for medical care. Researchers tracked nearly 30,000
Seventh-Day Adventists for a year to identify any differences in their need for health
care versus meat-eaters. The average number of chronic diseases was 1.03 in vegetarian
females, compared with 1.24 in nonvegetarian females. Among males, vegetarians averaged
0.79 chronic diseases and nonvegetarians averaged 0.93. In addition, vegetarian females
reported significantly fewer overnight hospitalizations and surgeries than did
nonvegetarian females, while vegetarian males reported fewer overnight hospitalizations
and X-rays than nonvegetarian males. Medication use was lower for vegetarian females and
males than for meat-eaters.

Mortality. In one study, vegetarian Adventists had a
substantially lower risk of fatal coronary disease, fatal diabetes and death from
any cause, especially among men compared with Adventists who use meat heavily.Research also shows that
vegetarians have a lower mortality rate from several types of cancer.
In other research,All-cause mortality showed a significant negative association with
green salad consumption and a significant positive association with consumption of eggs
and meat. For green salad and eggs, the association was stronger for women; for meat, the
association was stronger for men. All the observed associations were adjusted for age,
sex, smoking history, history of major chronic disease, and age at initial exposure to the
Adventist Church.Specifically,
some compounds in plants may help reduce overall inflammation. For example, laboratory and
nonhuman experiments indicate that plant sterols may lower the histamine reactions in
certain immune cell lines.

CONCLUSION
What matters in the end, of course, is that we can affect the quality of our lives with
our eating patterns. There may be no better way to achieve this goal than by eliminating
our consumption of animal foods and centering our diet on a well-balanced intake of plant
foods. The scientific literature shows that vegetarian eating offers far-reaching health
benefits, allowing people to reduce their risk of chronic diseases that plague modern-day
society, including hypertension, diabetes, and various types of cancer.
It is our hope that as more consumers become aware of these benefits, they will switch to
a vegetarian diet and thereby optimize their health and quality of life. In the process,
they will support the increasingly important ecological benefits of vegetarianism, which
allows us to conserve the natural resources used to produce animal foods that provide
limited nutritional value in return.

The
Authors
Gary Null, Ph.D., has authored more than 75 books on health and nutrition and numerous
articles published in research journals. He is Adjunct Professor, Graduate Studies, Public
Health Curriculum, at Fairleigh Dickinson University in Teaneck, N.J. Null holds a Ph.D.
in human nutrition and public health science from the Union Graduate School.

Martin Feldman, M.D., practices complementary medicine. He is an Assistant Clinical
Professor of Neurology at the Mount Sinai School of Medicine in New York City.

U.S.
Cancer Statistics Working Group. United States Cancer Statistics: 19992004 Incidence
and Mortality Web-based Report. Atlanta: U.S. Department of Health and Human
Services, Centers for Disease Control and Prevention and National Cancer Institute; 2007.
Available at: www.cdc.gov/uscs.